The world’s largest high-grade uranium mine is located in Canada: Cigar Lake

Cigar Lake it’s the most big mine Of uranium to the world. Located in Canadain the northern portion of the province of SaskatchewanCigar Lake is known for its very high uranium content, averaging about 17% of U_₃OR_₈in its mineralizations within ancient rocks over 1.6 billion years ago. With an overall production exceeding 70,000 metric tons less than twelve years Of activitythe mine today represents a technological point of reference in the extraction sector, thanks to the use of advanced techniques such as Jet Bore System and the bulk freezing. When we talk about uranium, in addition to Canada and Namibia, we must also consider the world leader in quantity, the Kazakhstanwhere its enormous deposits alone provide approximately 43% of all global uranium.

Where the largest mine in the world is located and the characteristics of Cigar Lake

The mine Cigar Lake, Canadain the northern portion of the province of Saskatchewan in Canada, is the largest underground high-grade uranium mine in the world and is located in the rich uranium basin of theAthabascain the north of the province of Saskatchewan (Canada), near the Lake Waterbury. The mine, active since 2014has produced, to date, over 70,493 tons uranium metrics. Estimated total reserves exceed 550 thousand tons, of which 322 thousands tons have been tested.

The mining structure extends underground for more 4 km and it grows on 6 levelsof which only two are mainly active today, for a maximum depth reached of 500 meters. On the surface, the mining complex extends for approx 10.42km². Two wells connect the surface to the underground extraction area.

High-grade uranium deposit geology

The uraniferous rocks of Cigar Lake are located at depths between 410 And 455 m. The mineralized body has a geometry lentiformelongated and flattened, and reaches an overall length of 1.95kmwhile the width varies between 25 and 100 m. The average thickness is approx 5.4 mwith a maximum peak of 15.7 m.

Uranium mineralizations are found within very ancient rocks and, in particular, in the contract between the sandstones of Athabasca Groupdeposited between the late Paleoproterozoic and the Mesoproterozoic (about 1,630 millions of years ago), and the crystalline rocks of Group of Wollastonconsisting mainly of metamorphic rocks (gneiss and metasediments) and igneous rocks older than 1,630 million years ago. There are two types of mineralization. The mineralizations ad high tenor of uranium and those a Bass tenor.

High-grade mineralizations are the only type economically exploitableare found along the contract surface between the Athabasca Group and the Wollaston Group and appear as bodies clayey massive containing very high concentrations of uranium minerals, such as uraninite And pitchblende. Here, the uranium content can reach values ​​up to86% Of U₃O₈ (oxide of uranium) at 0.5 m intervals. However, the average values ​​are around 16.68%. It is believed that these minerals were formed following reactions of oxidation-reduction occurred along the contact between oxidizing fluids and reducing fluids along the surface that separates the two rock groups.

The low-grade mineralizations, however, are found within fractures And veins present in the crystalline basement and, to a lesser extent, in the overlying sandstones. These secondary mineralizations are the result of movements tectonics and of reactivation Of faultswhich favored the circulation of fluids mineralising and the remobilization of pre-existing uranium.

The deposit also contains nickel, copper, cobalt, lead, zinc, molybdenum, arsenic And lands rarealthough in concentrations that are not economically exploitable.

Extraction technologies at Cigar Lake

In the Cigar Lake mine an innovative extraction method is used, the Jet Bore System (JBS). The method involves the preventive freezing of the mineralized body (and the surrounding rocks) through the use of a fluid refrigerantwith temperatures at –40 °Cpumped underground through pipes. The freezing process (bulk freezing) takes about a year to be completed and ensure mechanical stabilization of the excavation area.

Once frozen and stabilized, the JBS comes into operation. Very high pressure water jets, injected through a pilot hole into the mineralized body, they shatter and break down the mineral, which is then dragged downwards and comes out of the photo pilot itself in the form of an aqueous suspension. The disintegrated material is subsequently conveyed into a separation and pumping system, and then sent to the facilities Of treatment And refining closer.

The main advantage of this technology is that it is a indirect extractionas the staff never comes into contact with the mineralized body, thus ensuring high standards of safety operational.

A Brief History of Cigar Lake Concessions

The uranium deposits currently exploited in the Cigar Lake mine were discovered in the early 1900s 80s, although authorization for exploration and exploitation was only granted in 2002. The mine was supposed to come into operation in 2007but a serious one infiltration of waterwhich occurred in October 2006significantly delayed the start of operations. Construction work resumed in 2011 and uranium mining finally began in March 2014.

Currently, the mine belongs to Cigar Lake Joint Venture (CLJV), a consortium of three Canadian companies that share ownership and profits: Cameco Corporation (54.547%), Oran Canada Inc. (40.453%) And TEPCO Resources Inc. (5,000%). CLJV holds a mineral lease with the Province of Saskatchewan, which grants the right to extract minerals in exchange for the payment of royalties. This contract covers an area of ​​approximately 3.08 km²to which they are added 38 concessions mining in the surrounding region, which authorizes the consortium to explore and develop new deposits on public lands. The overall area of ​​concessions reaches 952.93 km²an area larger than the entire metropolitan area of Berlin (about 892 km²). The mining license is currently valid until 2031 and is renewable on ten-year terms.